POLYMER BULLETIN
·
2012
·Vol. 70
·期 2
·467-478
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IF 1.532
Yan Manqing,Yang Hongjun,Xing Xinming
Poly(ε-caprolactone- co -ethylene carbonate- co -ethylene oxide) (CL- co -EC- co -EO) copolymer was synthesized via ring-opening copolymerization of ε-caprolactone (CL) and 1,3-dioxolan-2-one with a metal-free phosphazene catalyst ( t -BuP 4 ). The monomer conversion and molecular weight in CL- co -EC- co -EO copolymer were characterized by nuclear magnetic resonance and gel permeation chromatography, respectively. Moreover crystallization behavior of CL- co -EC- co -EO copolymer was investigated by differential scanning calorimeter and wide-angle X-ray diffraction. The enzymatic degradation of the copolymer has been investigated by quartz crystal microbalance with dissipation. Our studies demonstrate that as PCL content in the copolymer decreases, the degree of crystallinity and crystal size decrease, while the enzymatic degradation rate increases. The copolymer exhibits layer-by-layer degradation.
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CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Jun Lu,Mingyue Xia,Jing Liang,Lie Zou,Xiaolong Liang,Yan Gao,Fei Li,Junfeng Gao,Jinxuan Liu
Cu 2 Y 2 O 5 with asymmetric atomic distance distribution was investigated for the first time in CO 2 electroreduction reaction (CO 2 RR). The high electrophilicity of Y not only regulates the electronic structure of Cu, but also acts as an electron dock to attract CO*, promoting its toward Y and effectively protecting the stability of Cu 2+ during the reduction process. In a Flow cell, CYO-850 achieves an exceptionally high selectivity of 70 % for ethylene, accompanied by a high partial current density of 200 mA cm −2 . In-situ infrared spectroscopy and density functional theory results indicate that interaction between Cu and Y promotes the dimerization of *OCCO intermediates and directs the CO 2 reduction pathway towards ethylene. This is the first report on the use of Y element in the field of CO 2 reduction.
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Materials Today Chemistry
·
2025
·
IF 6.7
Xiaotong Song,Junyuan Zhang,Weiqi Li,Huanying Li,Zhiguo Li,Xiaolong Xu,Changyu Liu,Jianbo Jia
Metal-organic framework (MOF)-derived carbon nanocomposites have been widely applied in electrocatalytic fields due to their simple synthesis, excellent conductivity, and high catalytic activity. In this study, ZIF-67 and MIL-101(Fe) were synthesized via liquid-phase precipitation and solvent thermal methods, respectively. Then, the two kinds of MOFs were ground and calcined with melamine to prepare flower-like carbon nanocomposites. Under the optimal conditions, the oxygen reduction reaction (ORR) onset potential (E onset = 1.019 V vs. reversible hydrogen electrode, RHE) and half-wave potential (E 1/2 = 0.866 V) of this prepared composite are both higher than those of commercial Pt/C catalyst (E onset = 0.971 V, E 1/2 = 0.838 V). The prepared nanocomposite exhibits a lower oxygen evolution reaction (OER) overpotential (η = 338 mV at 10 mA cm −2 ) than RuO 2 (η = 372 mV), demonstrating superior catalytic performance. The prepared nanocomposite achieves simultaneous enhancement in both ORR and OER bifunctional catalytic performances. The power density of a zinc-air battery (ZAB) assembled with the optimal nanocomposite was 2.65 times higher than that of the Pt/C + RuO 2 system. This study establishes a fundamental framework for the rational design of high-performance ORR/OER bifunctional catalysts, while pioneering new avenues for ZAB technology commercialization.
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Surfaces and Interfaces
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2025
·
IF 6.3
Jiangang Kang,Haihong Zhang,Yuehui He,Liang Wu,Hengdi Ye,Jinchao Wei
The novel Ni-Si intermetallic compounds are fabricated by elemental powder metallurgy. This study explores the synthesis of a series of catalysts (Ni-Si-M, M=Co, Fe, Mn) by alloying to augment the low-temperature efficiency of CO oxidation using Ni-Si intermetallic compounds. It is found the low-temperature catalytic activity of Ni-Si-Co, Ni-Si-Fe, and Ni-Si-Mn catalysts are significantly enhanced compared to the original Ni-Si. The catalytic activity among the catalysts ranks as follows: Ni-Si-Co > Ni-Si-Fe > Ni-Si-Mn > Ni-Si. The apparent activation energy (Ea) for Ni-Si-Co was the lowest at 57.3 kJ/mol, suggesting its efficient catalytic oxidation of CO. Additionally, the addition of Co, Fe and Mn elements actually promotes the generation of Ni 2+ as the CO adsorption site in the original Ni-Si. The addition of Co element also leads to the formation of Co 2+ as the adsorption site of O 2 in the process of CO oxidation reaction. The synergistic adsorption of Ni 2+ and Co 2+ to CO and O 2 promotes the CO oxidation reaction. Additionally, the catalysts demonstrate robust long-term stability in atmospheres containing H 2 O and SO 2 , with CO conversion initially suppressed but subsequently recovering and stabilizing at over 90%. This investigation offers novel insights into enhancing the low-temperature activity and stability of catalysts.
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ChemPlusChem
·
2025
·
IF 2.8
Wen Feng,Congyue Sun,Xiaojin Li,Xiliang Luo,Liu Wenqi
The exploitation of an efficient and stable oxygen reduction reaction (ORR) catalyst plays a crucial role in the slow kinetics of the cathode in proton exchange membrane fuel cells (PEMFC). In this study, a catalyst loaded with PtCo alloys on Co and N co-doped carbon nanotubes (PtCoNC) was synthesized for oxygen reduction reaction, which has high activity and stability. The carbon nanotube structure provides efficient transport channels for reactant exchange and product transport, as well as provides a wealth of triple-phase sites, that improves the utilization of Pt. Further, the PtCoNC catalyst exhibits robust metal-support interactions, which can be attributed to the anchoring of the Co-Nx sites to Pt. Theoretical calculations indicating an increase in binding energy and a reduction in layer spacing provide conclusive verification of the presence of augmented interactions between PtCo nanoparticles and the support. As a result, the low Pt-loaded (0.025 mg cm-2) PtCoNC catalyst demonstrates superior ORR activity to that of commercial Pt/C with an impressive half-wave potential of 0.893 V in 0.1 M HClO4 solution. At 0.9 V, its mass activity and specific activity are 3 and 2.6 times that of commercial Pt/C, respectively. It also shows better stability in acidic environment.
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PubMed
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FUEL
·
2025
·
IF 7.5
Yongpeng Ma,Jianghui Du,Yifei Wu,Haobing Yan,Ruiqi Liu,Xiaojing Zhang,Hongzhong Zhang,Liming Zhou,Wenjun Huang
Among the diverse pollutants emitted from coal-fired and non-ferrous metal smelting flue gas, Hg 0 and CO have emerged as globally concerning environmental pollutants. However, the simultaneous abatement of multiple pollutants remains a critical challenge to be addressed. In this study, cobalt nanoclusters (Co NCs) were anchored on the terminal oxygen of Ti-O on Ti 3 C 2 MXene and formed asymmetric oxygen vacancies Co-Ov-Ti via a one-step hydrothermal method, yielding Co NCs/Ti 3 C 2 MXene with a morphology of hierarchical nanosheet-assembled spheres for Hg 0 and CO catalytic oxidation. Co NCs/Ti 3 C 2 MXene exhibited excellent 44 % and 52 % of Hg 0 and CO simultaneous removal efficiency at the optimal temperature of 250 °C, respectively. DFT calculations combined with energy barrier modeling were employed to investigate the reaction pathways and energy variations during the catalytic oxidation of Hg 0 and CO. Specifically, Hg 0 oxidation follows the Eley-Rideal mechanism, with a rate-determining energy barrier of 2.11 eV, while CO oxidation adheres to the Langmuir-Hinshelwood mechanism, featuring a rate-determining barrier of 0.17 eV. In the co-catalytic oxidation process, competitive adsorption between Hg 0 and CO was observed, primarily manifested as competition for Ov on the catalyst surface. This study provides a novel strategy for the synergistic control of multi-pollutants in industrial flue gas.
研究领域:
环境催化
·
材料科学
·
大气污染控制
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物理化学
·
纳米材料
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FUEL
·
2024
·
IF 6.7
Anqi Li,Xiaoyu Qian,Mengyan Han,Zhichun Li,Xiaobo He,Guofeng Wang
Electrochemical catalytic water splitting is considered as a promising technique for green hydrogen production, and highly active catalysts toward cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER) are required, especially bifunctional ones. In this work, the bifunctional catalysts with Co-CoO x @N, O co-doped carbon (NOC) hybrid nanostructures have been prepared via pyrolysis of ZIF-Co with assistance of a small amount of KNO 3 . KNO 3 plays important roles in tuning the inner and the outer structures of Co-CoO x @NOC hybrid nanostructures. The proposed S Ov , which is defined as the content of oxygen vacancy (O v ) per unit surface area of the inner Co-CoO x nanoparticle, and charge transfer resistance ( R ct ) are used as the descriptors of the inner structures, while hydrophilicity (or contact angle) is applied as the main feature of the outer structures. S Ov , R ct and hydrophilicity are well tuned by the fed mass of KNO 3 , and a moderate fed mass is the key to balancing S Ov , R ct and hydrophilicity and further is beneficial to accelerating specific and intrinsic activity for both HER and OER . Thus, the bifunctional HER/OER specific and intrinsic activity is peaked by Co-CoO x @NOC-0.025KNO 3 with a moderate fed mass of KNO 3 of 0.025 g, such as j s-250-HER of 539.22 μA cm -2 BET and j s-350-OER of 129.83 μA cm -2 BET at the HER and OER overpotentials of 250 and 350 mV, respectively, also corresponding to high turnover frequencies of 6.653 and 0.801 s −1 , respectively. The optimal catalyst also has high apparent activity, such as achieving high HER and OER current densities of 500 mA cm −2 , only requiring low overpotentials of 273.1 and 382 mV, respectively. It promotes overall water splitting with a high current density of 500 mA cm −2 at a cell voltage of ∼ 1.63 V, showing the high HER and OER Faradaic efficiencies of ∼ 98.2 and ∼ 98.0 %, respectively.
研究领域:
材料科学
·
电化学
·
催化科学
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Journal of Macromolecular Science Part B-Physics
·
2022
·
IF 1.366
Meimei Guo,Zhihua Zhou,Wenjuan Liu,Tianlong Huang,Wei Wu,Jianglong Duan,Meiling Yi,Chao Zhang,Xiao He,Jinxing Chen,Jiaming Gu,Jianjun Fang
Polymer/bioceramic composite scaffolds have gained importance in treating bone defects. In this paper we described a novel degradable scaffold material for bone tissue repairing prepared by combining poly(lactide-co-glycolide-co-ε-caprolactone) (PLLGC) and 1,4-butanediamine-modified poly(lactide-co-glycolide) (BMPLGA) with nano-biaoactive glass (NBAG) and nano β-tricalcium phosphate (β-TCP). The composite scaffolds were characterized by using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The FTIR results indicated that the inorganic fillers of NBAG and β-TCP were successfully incorporated into the PLLGC/BMPLGA matrix. The influences of the inorganic filler content and freezing temperature on the porosity and compressive strength of the composite scaffolds were studied. The composite scaffolds showed an interconnected pore structure with the pore size ranging from 20 to 100 μm depending on the freezing temperature and the inorganic fillers. The compressive strength was enhanced with increasing content of the inorganic fillers and the freezing temperature; however, the porosity decreased. We suggest the PLLGC-BMPLGA/NBAG-β-TCP composite scaffolds have great potential for application in bone tissue regeneration.
研究领域:
生物材料
·
组织工程
·
高分子科学
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生物医学工程
·
材料表征
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2023
·
IF 4.2
Jiahui Xu,Jia-qi Bai,Wenjie Si,Yunhai Zhang,Jiazhao Tan,Mengdie Cai,Qin Cheng,Song Sun
Non-noble metals have attracted worldwide attention for the catalytic hydrogenation of halonitrobenzene due to their high activity, low price, and abundance on Earth. However, the construction of effective and stable non-noble-metal catalysts for the selective hydrogenation of halonitrobenzene to haloaniline by a simple method remains challenging. Herein, we report a facile one-pot method for the synthesis of N,S-co-doped mesoporous carbon-supported non-noble-metal catalysts through carbonization of a mixture of metallic precursors and 2-aminothiazole in molten ZnCl2. The prepared Co-NSPC catalyst showed excellent activity and selectivity with a turnover frequency of 84.4 h–1 in the hydrogenation of p-chloronitrobenzene to p-chloroaniline. Furthermore, Co–Nx was found to be the main active site for this reaction on the basis of characterization and experimental data, and the introduction of S promoted the formation of Co–Nx sites. Moreover, the Co-NSPC-800 catalyst can be reused at least four times and applied to the hydrogenation of 10 kinds of halogenated nitrobenzenes with excellent selectivity.
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IONICS
·
2023
·Vol. 29
·期 9
·3473-3482
·
IF 2.8
Liu Xiaofei,Wu Yuandong,Mei Dajiang,Wen Shaoguo
The pyrochlore-type material Co 2 Sb 2 O 7 @C was synthesized through high-temperature solid-state reactions. Co 2 Sb 2 O 7 and Co 2 Sb 2 O 7 @C were characterized by PXRD, XPS, SEM, EDS, and BET. At the current density of 200 mA g −1 , the first cycle discharge capacity of Co 2 Sb 2 O 7 @C is 1266 mAh g −1 . After 100 cycles, the specific discharge capacity can still reach 463 mAh g −1 , which is higher than the 76 mAh g −1 of Co 2 Sb 2 O 7 . With the increase in scanning rate, the contribution rate of the Co 2 Sb 2 O 7 @C pseudo-capacitor varies from 69.2 to 92.5%. The electrochemical performance is due to the conversion and alloying reaction of Li 3 Sb, the coating of amorphous carbon, and the contribution of pseudo-capacitance.
研究领域:
材料科学
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电化学
·
储能技术
·
纳米技术
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iScience
·
2022
·
IF 6.107
Meng Wang,Yan Zhang,Wenpo Shan,Yunbo Yu,Jingjing Liu,Hong He
The thermal stability of the catalysts is of particular importance but still a big challenge for working under harsh conditions at high temperature. In this study, we report a strategy to improve the thermal stability of the ceria-based catalyst via introducing Sn. XRD, Rietveld refinement, and other characterizations results indicated that the formation of Sn-Co solid solution plays a key role in the thermal stability of the catalyst. The developed ternary 3%Co/Ce 0.5 Sn 0.5 O 2 catalyst not only exhibits outstanding thermal stability and resistance to SO 2 and H 2 O for soot oxidation from diesel vehicle exhaust but also remains extraordinary thermal stability for CO oxidation. Remarkably, even after thermal aging at 1000°C, it still possessed high catalytic activity similar to that of the fresh catalyst.
研究领域:
催化材料
·
环境科学
·
化学工程
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PubMed
高影响因子
CATALYSIS TODAY
·
2026
·
IF 5.1
Nan Yang,Yaru Xue,Zehui Ma,Furang Li,Li Dong,Xiaoxuan Yin,Junhao Liu,Fei Wang,Jianye Fu,Xinmei Liu,Yuchao Lyu
The hydrodeoxygenation (HDO) of lignin-derived guaiacol offers an alternative to fossil-based routes for cyclohexanol production. However, the guaiacol HDO involves multiple parallel and sequential reactions, making the control of reaction pathways particularly challenging. In this work, Co-Zn-based HDO catalysts were synthesized using layered double hydroxide (LDH) as a precursor. The Co particle size decreases and electron density increases, while oxygen vacancy (Ov) concentration rises compared to monometallic Co, yielding higher activity and cyclohexanol selectivity. Most importantly, kinetic study reveals that electron density of Co plays a determining role in governing the HDO pathway. The guaiacol hydrogenation mainly follows two pathways over the Co-based catalyst: guaiacol → phenol → cyclohexanol (Pathway Ⅰ) and guaiacol → phenol → cyclohexanone → cyclohexanol (Pathway Ⅱ). Electron rich Co facilitates C aryl -OCH 3 bond cleavage of guaiacol to form phenol. It also selectively enhances adsorption and hydrogenation of aromatic ring while keeps the hydroxyl group intact as confirmed by the DFT calculations, favoring conversion of phenol to cyclohexanol (Pathway Ⅰ) rather than cyclohexanone (Pathway Ⅱ). These findings provide theoretical guidance for the rational catalyst design and regulation of reaction pathways in guaiacol hydrodeoxygenation.
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